Qui peut m'aidé svp c'est pour demain et j'y comprend rien

Ineed i been stuck on this question since yesterday

Ebuka's monthly rent is $750. if ebuka pays the rent late, his landlord charges 4% interest per week that the payment is late. write a function that gives the total cost r(t), in dollars, of ebuka's rent if he pays it t weeks late.

Hello, i need compare km^2 and km. what's difference in this?